Bistable fluid device



Sept. 1 1954 w. J. SEATON BISTABLE FLUID DEVICE 4420 m FDnEbO mmDwmwma O D E Filed Sept. 17, 1962 INVENTOR. W/LL/AM J. SEAm/v 7% ATTORNEY NW Q hm 9w QM & 5% All wmnmmwmq A 93. NM

MN Q 2 NW womnow wmamwmmm hzfiwzoo 3 MN United States Patent 3,148,692 BISTABLE FLUID DEVICE William J. Seaton, Salt Lake City, Utah, assignor to Sperry Rand Corporation, Great Neck, N.Y., a corporation of Delaware Filed Sept. 17, 1962, Ser. No. 223,939

3 Claims. (Cl. 137-815) This invention relates to a fluid operated device which is stable in two modes of operation without requiring moving parts.

The present invention utilizes fluid flow to perform functions analogous to electrical bistable multivibrators without requiring delicate electrical apparatus or a source of electrical energy. Further the present invention operates without moving parts and switches from one stable state of operation to another without requiring any moving elements other than a fluid pulse. The present invention is therefore extremely reliable and suitable for operation over a wide range of environmental conditions.

It is an object of the present invention to provide a bistable fluid device that requires no moving parts.

It is another object of the present invention to provide a bistable fluid device that performs functions analogous to functions performed by known electrical apparatus.

It is a further object of the present invention to provide a bistable fluid device that remains reliable in operation although subjected to a wide variation in environmental conditions.

The above objects are accomplished by utilizing the energy of a pressure fiuid to switch from one stable state of operation to another by means of a cooperative pair of aspirating-type devices.

The drawing is a schematic diagram of a bistable fluid device incorporating the present invention. The bistable fluid device includes a hollow spherical chamber 11 having a restricting inlet 12 that is connected to a constant pressure fluid source 13 which provides a pressure fluid 14 at a pressure of P The chamber 11 also has a restricting outlet 15 which may be connected to the inlet of the source 13 or may exhaust to the atmosphere at a pressure P which is less than P Similarly, another hollow spherical chamber has its restricting inlet 21 connected to the pressure fluid source 13 and its restricting outlet 22 connected to the inlet of the source 13 or to exhaust to atmosphere at the pressure P An aspirating conduit 23 has one end connected to the chamber 11 while its other end terminates in a nozzle 24 disposed in the outlet 22 in a manner to aid in exhausting the fluid from the chamber 20. Similarly an aspirating conduit 25 has one end connected to the chamber 20 while its other end terminates in a nozzle 26 which is disposed in the outlet 11 to aid in exhausting the fluid from the chamber 11. An input conduit 30 may be connected to the chamber 11 and is adapted to receive a fluid pressure input signal as indicated by the legend. An output conduit 31 may have one end connected to the chamber 20 While its other end provides a fluid pressure output signal as indicated by the legend.

The chambers 11 and 20 as well as the unrelated elements are substantially identical in size. The restricting inlets 12 and 21 restrict the amount of fluid entering the respective chambers 11 and 20 in a manner to be explained while the restricting outlets 15 and 22 provide a venturi effect which in conjunction with the nozzles 26 and 24 respectively causes an aspirating eflect in a manner to be explained.

In operation, a constant pressure fluid 14 is supplied by the source 13 at a pressure P and passes through the restrictions 12 and 21 into chambers 11 and 20 3,148,692 Patented Sept. 15, 1964 respectively to exhaust through outlets 15 and 22 at a pressure P The fluid from the chamber 11 passes through the conduit 23 and issues from the nozzle 24 at a high velocity thereby tending to lower the pressure in the chamber 20 in accordance with Bernoullis theorem thus inducing an aspirating action. Similarly, the fluid issuing through the nozzle 26 from the chamber 20 tends to lower the pressure in the chamber 11. Due to a slight difference in pressure in one of the chambers, the fluid pressure in one chamber will be approximately equal to P while that of the other chamber will be approximately equal to P2.

Assuming chamber 20 is at P and chamber 11 is at P the apparatus 10 will remain stable because the higher pressure P in the chamber 20 provides a high velocity fluid stream from the nozzle 26 thereby lowering the pressure in the chamber 11 by creating a suction through the venturi restrictingoutlet 15. The low fluid pressure in the chamber 11 creates a relatively low velocity stream to issue from the nozzle 24 thereby creating very little suction from the venturi restricting outlet 22 and retaining the relatively high pressure P in the chamber 20.

To cause the device 10 to switch to its other bistable state, an input signal, for example, in the form of an input pulse of pressure P is applied to the input conduit 30. This causes an increase in pressure in the chamber 11 thereby increasing the velocity of the fluid issuing from the nozzle 24 to a higher velocity than that issuing from the nozzle 26 which reduces the pressure in the chamber 20 to less than that in the chamber 11. With the pressure decreased in the conduit 25 less fluid passes through the nozzle 26 thereby decreasing the suction through the outlet 15 while aiding the pressure increase in chamber 11 and the fluid flow from nozzle 24.

To switch back again to the original condition explained above, an input signal of pressure P is applied to the input conduit 30. In either event, a fluid pressure output signal may be taken, for example, from the chamber 20 through the output conduit 31 thereby providing a bistable fluid device.

While the invention has been described in its preferred embodiments, it is understood that the words which have been used are words of description rather than of limitation and that changes within the purview of the appended claims may be made without departing from the true scope and spirit of the invention in its broader aspects.

What is claimed is:

1. A bistable fluid device comprising (1) a first chamber having a first restricting inlet adapted to receive a fluid under pressure and a first restricting outlet,

(2) a second chamber having a second restricting inlet adapted to receive said fluid under pressure and a second restricting outlet,

(3) a first nozzle responsive to the pressure of the fluid in said second chamber and disposed in said first outlet for aiding in exhausting the fluid from said first chamber,

(4) a second nozzle responsive to the pressure of the fluid in said first chamber and disposed in said second outlet for aiding in exhausting the fluid from said second chamber,

(5 an input conduit connected to one of said chambers for providing a fluid pressure input signal, and

(6) an output conduit connected to one of said chambers for providing a fluid pressure output signal.

2. A bistable fluid device comprising (1) means for providing a fluid under constant pressure,

(2) a first chamber having a first restricting inlet con- 3 nected to receive said fluid and a first restricting outlet,

(3) a second chamber having a second restricting inlet connected to receive saidfluid and a second restricting outlet,

(4) a first aspirating conduit having one end connected to said first chamber and the other end disposed in said second outlet for aiding in exhausting the fluid from said second chamber,

(5) a second aspirating conduit having one end connected to said second chamber and the other end disposed in said first outlet for aiding in exhausting the fluid from said first chamber,

(6) said first and second chambers, inlets, outlets, aspirating conduits and nozzles being substantially identical,

(7) an input conduit connected to one of said chambers for providing a fluid pressure input signal, and

(8) an output conduit connected to one of said chambers for providing a fluid pressure output signal.

7 3. A bistable fluid device comprising (1) means for providing a fluid under constant pressure,

(2) a first chamber having a first restricting inlet connected to receive said fluid and a first restricting outlet,

(3) a second chamber having a second restricting inlet connected to receive said fluid and a second restricts ing outlet, .1

(4) a first aspirating conduit having one end connected to said first chamber and the other end terminating in a first nozzle disposed in said second outlet for creating a venturi effect tending to exhaust said second chamber,

(5) a second aspirating conduit having one end connected to said second chamber and the other end terminating in a second nozzle disposed in said first outlet for creating a venturi eflect tending to exhaust said first chamber,

(6) said first and second chambers, inlets, outlets, aspirating conduits and nozzles being substantially identical,

(7) an input conduit connected to said first chamber for providing a fluid pressure input signal, and

(8) an output conduit connected to said second chamber for providing a fluid pressure output signal.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A BISTABLE FLUID DEVICE COMPRISING (1) A FIRST CHAMBER HAVING A FIRST RESTRICTING INLET ADAPTED TO RECEIVE A FLUID UNDER PRESSURE AND A FIRST RESTRICTING OUTLET, (2) A SECOND CHAMBER HAVING A SECOND RESTRICTING INLET ADAPTED TO RECEIVE SAID FLUID UNDER PRESSURE AND A SECOND RESTRICTING OUTLET. (3) A FIRST NOZZLE RESPONSIVE TO THE PRESSURE OF THE FLUID IN SAID SECOND CHAMBER AND DISPOSED IN SAID FIRST OUTLET FOR AIDING IN EXHAUSTING THE FLUID FROM SAID FIRST CHAMBER, 